JBRARY  OF 


UNIVERSITY  OF  ILLINOIS 
AT  URBANA-CHAMPAIGN 


AGRICULTURE 


CIRCULATING 


CHECK  FOR  UNBOUND 
CIRCULATING  COPY 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  NO.  274 


SOME  TESTS  IN  THE  CULTURE 
OF  PEPPERS 


BY  J.  W.  LLOYD 


URBANA,  ILLINOIS,  APRIL,  1926 


SUMMARY 

Green  peppers  of  the  large  type  have  become  very  popular  for 
salads  and  for  stuffing.  Their  culture  is  profitable  where  good  yields 
can  be  secured.  Under  Illinois  conditions,  the  use  of  large,  well-grown, 
potted  plants  is  favorable  to  early  bearing  and  large  total  production. 
The  tests  reported  in  this  bulletin  were  made  to  determine  other  factors 
affecting  yields. 

Altho  the  pepper  plant  will  withstand  considerable  dry  weather, 
the  yields,  as  an  average  for  five  years,  were  increased  about  15  per- 
cent by  supplementing  the  natural  rainfall  with  overhead  irrigation. 

Neither  the  use  of  nitrogen  in  the  form  of  nitrate  of  soda,  nor  of 
phosphorus  in  the  form  of  bone  meal,  resulted  in  any  consistent 
increases  in  the  yields  of  peppers. 

A  comparison  of  six  varieties  indicated  that  Neapolitan  Salad  was 
the  earliest,  but  that  Sweet  Mountain  was  the  heaviest  yielder. 
Chinese  Giant  was  the  poorest  yielder. 


FIG.  1. — SWEET  MOUNTAIN  PEPPER 
This  variety  yielded  an  average  of  3  pounds  of  peppers  to  a  plant. 


SOME  TESTS  IN  THE  CULTURE 
OF  PEPPERS 

By  J.  W.  LLOYD,  Chief  in  Olericulture 

Green  peppers  of  the  large,  mild  or  sweet  type,  used  in  salads 
and  for  stuffing,  have  increased  greatly  in  popularity  within  the  last 
few  years.  Their  use  in  salads  especially  has  recently  become  quite 
important,  and  they  are  shipped  from  the  South  to  northern  markets 
at  seasons  of  the  year  when  the  northern  home-grown  product  is 
not  available.  Illinois  gardeners  have  had  trouble  in  taking  advan- 
tage of  this  increased  demand,  because  of  failure  to  get  satisfactory 
yields.  It  is  a  common  occurrence  in  the  North  for  peppers  to  produce 
very  few  fruits  until  late  in  the  fall,  and  then  to  be  caught  by  frost 
with  the  main  crop  still  on  the  plants  too  immature  to  be  of  value. 

Some  tests  were  therefore  planned  by  this  Station  with  a  view 
to  developing  a  method  by  which  growers  in  Illinois  would  be  enabled 
to  produce  larger  yields  before  the  close  of  the  growing  season.  The 
tests  were  made  on  rich  garden  soil  of  the  brown  silt  loam  type,  at 
Urbana,  starting  in  1919  and  continuing  thru  the  season  of  1923.  They 
included  the  growing  of  peppers  with  and  without  irrigation;  with  and 
without  applications  of  nitrate  of  soda;  with  and  without  bone  meal; 
as  well  as  a  comparison  of  different  varieties. 

Previous  experience  had  shown  that  large,  well-grown,  potted 
plants  have  a  much  better  chance  of  producing  satisfactory  yields 
before  the  close  of  the  season  than  have  plants  that  are  small,  young, 
or  poorly  developed  at  the  time  they  are  set  in  the  field.  A  pepper 
plant  normally  continues  to  bear  until  killed  by  frost,  and  an  early 
start  gives  it  a  longer  bearing  season.  All  the  pepper  plants  used  in 
the  present  tests  were  grown,  therefore,  from  early-planted  seed,  and 
handled  in  a  manner  to  put  them  in  ideal  condition  when  the  time  for 
setting  in  the  field  arrived. 

METHOD  OF  CONDUCTING  THE  TESTS 

The  pepper  seed  was  sown  in  flats  in  a  warm  greenhouse  in  March. 
As  soon  as  the  plants  were  large  enough  to  handle  to  advantage,  they 
were  shifted  to  2% -inch  pots,  and  were  later  transferred  to  4-inch 
pots.  At  the  time  they  were  set  in  the  field  the  plants  were  large  and 
well  developed,  usually  showing  buds  and  sometimes  blossoms.  These 
potted  plants  suffered  very  little  check  in  growth  when  placed  in  the 
open  ground. 

Four  rows  of  pepper  plants  were  set  in  the  field,  two  where  they 
could  be  irrigated  by  the  overhead  Skinner  system.  The  rows  were 

331 


332 


BULLETIN  No.  274 


[April, 


3y2  feet  apart  and  the  plants  were  placed  2  feet  apart  in  the  row.  The 
various  lots  were  designated  as  follows: 

Lot  1.  Not  irrigated  nor  fertilized  (check) 

Lot  2.  Not  irrigated,  but  fertilized  with  bone  meal 

Lot3.  Irrigated  but  not  fertilized 

Lot  4.  Irrigated  and  fertilized  with  nitrate  of  soda 

The  object  of  making  these  combinations  of  treatments  was  to 
determine  whether  fruitfulness  in  the  pepper  could  be  stimulated  by 

the  use  of  phosphorus,  which  is 
supposed  to  increase  the  yields  of 
fruit-bearing  plants;  or  whether 
fruitfulness  in  the  case  of  this 
plant  might  be  associated  with  a 
strong  vegetative  growth.  Irriga- 
tion was  resorted  to  as  one  means 
of  promoting  vegetative  growth. 
With  a  view  to  stimulating  such 
growth  still  further,  if  possible, 
nitrate  of  soda  was  used  in  addi- 
tion to  irrigation  on  one  of  the  lots. 
Six  varieties — Neapolitan  Salad, 
Sweet  Mountain,  Crimson  Giant, 
Magnum  Dulce,  Chinese  Giant, 
and  Ruby  King — were  included  in 
the  tests  each  year  except  in  1920, 
when  Ruby  King  was  omitted. 
Each  variety  was  grown  under 
each  of  the  treatments  mentioned. 

In  1919  only  9  plants  of  each  variety  were  grown  under  each 
treatment;  in  1920  and  1921,  15  plants  of  each  variety  were  used,  and 
in  1922  and  1923,  20  plants  of  each  variety. 

The  bone  meal  was  applied  at  the  rate  of  2  ounces  per  plant,  and 
was  mixed  thoroly  with  the  soil  at  the  time  the  plants  were  set.  The 
nitrate  of  soda  was  used  at  the  rate  of  1  ounce  per  plant  for  the  season, 
but  was  applied  %  ounce  at  a  time.  The  first  application  was  usually 
made  about  four  weeks  after  the  plants  were  set  in  the  field,  and  the 
second  applicaton  about  three  weeks  later. 

The  peppers  were  picked  when  in  the  right  condition  for  market, 
that  is,  when  they  appeared  to  have  reached  their  maximum  size  but 
were  still  green.  A  number  of  pickings  were  required  to  harvest  the 
crop.  When  the  weather  was  warm  and  the  peppers  were  developing 
rapidly,  it  was  found  necessary  to  pick  over  the  plantation  once  a 
week  to  get  the  crop  in  optimum  condition.  When  the  weather  was 
cooler,  less  frequent  picking  was  necessary.  The  number  of  pickings 
each  year  was  as  follows:  1919,  twelve;  1920,  fifteen;  1921,  twelve; 
1922,  nine;  1923,  six. 


FIG.  2. — TYPE  OF  PLANT  USED  IN  THE 
TESTS.    GROWN  IN  4-lNCH  POT 


1926} 


SOME  TESTS  IN  THE  CULTURE  OF  PEPPERS 


333 


In  1923  the  weather  was  very  cool  and  the  crop  was  cut  off  by 
frost  on  September  12.  In  the  other  years,  picking  was  continued  into 
October.  Dates  of  planting,  transplanting,  and  harvesting  are  given 
in  Table  1. 


TABLE  1. — DATES  ON  WHICH  PEPPERS  WERE  PLANTED  AND  HARVESTED 


1919 

1920 

1921 

1922 

1923 

Seeded  

Mar.  19 

Mar.  .5 

Mar.  19 

Mar.  7 

Mar.  9 

Shifted  to2V£-inch  pots  

Apr.  11 

Mar.  29 

Apr.  12 

Mar.  23 

Apr.  2 

Shifted  to  4-inch  pots       .... 

May  10 

Apr.  25 

May  5 

Apr.  17 

Apr.  23 

Set  in  field  

June  13 

May  28 

June  1 

May  24 

June  2 

First  picking  

July? 

June  25 

June  24 

June  27 

July  2 

Last  picking  

Oct.  8 

Oct.  9 

Oct.  8 

Oct.  9 

Sept.  12 

YIELDS  INCREASED  ABOUT  15  PERCENT 
BY  IRRIGATION 

Whenever  the  rainfall  was  insufficient  to  keep  the  peppers  well 
supplied  with  moisture,  the  two  rows  planted  near  the  irrigation  pipe 
were  thoroly  watered.  The  results  of  irrigation  are  indicated  in 
Table  2. 

In  1919  all  varieties  produced  larger  yields  without  irrigation,  and 
in  1920  the  average  yield  was  slightly  greater  from  the  non-irrigated 
plants,  owing  to  the  relatively  light  yield  of  one  variety  under  irriga- 
tion. In  the  other  three  years,  however,  the  yields  of  all  varieties  were 
greater  from  the  irrigated  plants ;  and  the  five-year  average  for  all  va- 
rieties shows  an  increase  in  yield  of  15  percent  apparently  due  to 
irrigation. 


NITRATE  OF  SODA  FAILS  TO  INCREASE  YIELD 

For  all  varieties  during  all  five  years,  in  20  trials  out  of  29,  the 
nitrated  plants  yielded  less  than  the  plants  without  nitrate  (Table  3). 
Four  of  the  varieties,  as  an  average  of  the  five  years,  yielded  less 
with  the  nitrate  treatment  than  without  it;  the  other  two  varieties 
yielded  slightly  more  with  nitrate.  The  five-year  average  yield  for  all 
varieties  combined  was  slightly  in  favor  of  the  plants  that  were 
grown  without  nitrate. 

It  is  quite  evident  that  the  yielding  propensities  of  the  plants 
were  not  improved  by  the  applications  of  nitrate  of  soda. 

BONE  MEAL  GIVES  NO  CONSISTENT  GAINS 

Under  the  conditions  of  this  experiment,  no  consistent  advantage 
was  derived  from  the  use  of  bone  meal  (Table  4).  In  1921  the  yields 


334 


BULLETIN  No.  274 


[April, 


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SOME  TESTS  IN  THE  CULTURE  OF  PEPPERS 


335 


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Average  

336  BULLETIN  No.  274 

were  distinctly  better  from  the  plants  treated  with  bone;  but  in  all 
other  years  the  average  yields,  including  all  varieties,  were  lower  from 
the  bone-treated  plants  than  from  the  untreated  plants.  Furthermore, 
the  five-year  average  yield  for  all  varieties  combined  was  slightly 
greater  from  the  untreated  plants. 

COMPARISON  OF  VARIETIES  FOR  EARLY 
AND  LATE  USE 

Marked  differences  were  discovered  in  the  yields  of  the  six  varie- 
ties of  peppers  included  in  these  tests. 

For  the  sake  of  making  a  fair  comparison  of  the  varieties,  early 
yields  and  total  yields  of  all  six  varieties  as  grown  without  irrigation 
or  special  fertilizer  treatment,  are  tabulated  in  Table  5.  All  peppers 
harvested  before  August  15  were  considered  "early."  Ordinarily  only 
a  relatively  small  proportion  of  the  crop  was  picked  before  that  date. 
Some  varieties,  however,  produced  a  much  larger  yield  of  early  pep- 
pers than  did  other  varieties.  Neapolitan  Salad  was  the  outstanding 
variety  so  far  as  earliness  was  concerned,  while  Chinese  Giant  and 
Magnum  Dulce  were  notably  deficient. 

So  far  as  total  yields  were  concerned,  Sweet  Mountain  outyielded 
all  the  other  varieties,  its  average  yield  for  the  five-year  period  as 
grown  under  all  four  treatments  being  more  than  double  that  of  Chi- 
nese Giant,  the  lowest  yielding  variety.  Furthermore,  Sweet  Moun- 
tain was  second  only  to  Neapolitan  Salad  in  average  yield  of  early 
peppers.  Since  Neapolitan  Salad  is  of  rather  small  size  and  suitable 
only  for  salad,  rather  than  being  adapted  also  to  stuffing,  Sweet 
Mountain  is  the  better  variety  for  general  use,  both  early  and  late, 
when  grown  on  brown  silt  loam  under  the  conditions  obtaining  in 
the  corn  belt.  It  is  of  course  possible  that  Chinese  Giant  might 
do  relatively  better  on  some  other  soils  or  under  other  conditions. 
The  important  point  brought  out  by  these  tests  is  that  there  are  great 
differences  in  yields  of  different  varieties,  and  each  gardener  should 
grow  a  variety  that  will  give  large  yields  under  his  soil  and  climatic 
conditions. 

CONCLUSIONS 

1.  It  is  feasible  to  grow  peppers  on  brown  silt  loam  as  ordinarily 
fertilized  for  market  gardening  purposes,  without  special  treatment 
with  commercial  forms  of  nitrogen  or  phosphorus. 

2.  Peppers  will  withstand  considerable  dry  weather,  tho  the  yields 
may  be  somewhat  increased  by  an  abundant  supply  of  moisture. 

3.  Treatment  with  nitrate  of  soda  in  addition  to  irrigation  seems 
to  be  detrimental  to  the  yield. 

4.  Varieties  of  peppers  differ  widely  in  productiveness.  Under  the 
conditions  of  these  tests,  Sweet  Mountain  proved  to  be  a  much  heavier 
yielder  than  any  of  the  other  five  varieties  tested. 


UNIVERSITY  OF  ILLINOIS-URBANA 


